Oil filled fuse cutout with arc interrupting means



MEANS May 5, 1964 R. s. BENNETT OIL FILLED FUSE CUTOUT WITH ARC INTERRUPTING 4 Sheets-Sheet l Filed Dec. 9, 1960 May 5, 1964 R. s. BENNETT 3,132,226

OIL FILLED FUSE CUTOUT WITH RC INTERRUPTING MEANS 4 Sheets-Sheet 2 Filed Dec. 9, 1960 ,.l p. a? a E mm @v uw Pn. wf s. n ww m Tlv TIM f. w M .m/M, P? H QN om vwff vm, l ww .I n @m I .I L l I f 1i uw S @v NN Nv MEANS May 5, 1964 R, s'. BENNETT OIL FILLED FUSE CUTOUT WITH ARC INTERRUPTING 4 Sheets-Sheet 3 Filed DSO. 9, 1960 Edo/6 5 B61212672 j y@ Hfs WM/veg.

May 5, 1954 R. s. BENNETT 3,132,226

OIL. FILLED FUSE CUTOUT WITH ARC INTERRUPTING MEANS Filed Dec. 9, 1960 4 Sheets-Sheet 4 Patented May 5, 1964 3,132,226 UIL FILLED FUSE CUlUUl WITH ARC HNTERRUPTING MEANS Raiph S. Bennett, Pittsfield, Mass., assigner to General ElectricCompany, ,a corporation of New York- Filed Dec.; 9, i969, Ser. No. 74,879 Claims, (Cl. 20d-15d) This invention relates to oil filled, fuse cutouts and more particularly to an oil filled, fuse cutout with arc interrupting means.

In the oil filled, fuse cutout field such as, for example, the so-called subway, oil filled, fuse cutouts, the cutouts utilize an oil for an insulatingmedium in a casing and a fusible element immersed in the oil for interrupting over` currents. In general, the cutout is also utilized as a manually-operated switch in order to open the circuit in whichthe oil filled, fuse cutout is utilized. In opening the circuit by the manual operationof theV oil filled, fuse cutout, a large `arc is generally drawn between the fixed high voltage contacts and the movable contacts of the switching means. Depending upon the voltageA and current at which the oil filled, fuse cutout is operating, the arc which is drawn on the opening of the cutout may have an extremely large amount of energy which is dissipated in the insulating oil. It kwill be obvious that without some special control means,the arc may be drawn out to dangerous lengths so that it may tend to strike to the grounded parts of the cutout, causing a shortcircuit and possibly dangerous pressures in the cutout. in some instances, the high energy of the arc has very deleterious effects on the oil, leading to the rapidy deterioration of the oil as an adequate insulating medium. Further, should an arc of sufciently high energy be drawn upon opening of the cutout, or persist for a sufiicient duration, it is possible that the high pressure generated by the arc would be sufficient to severely damage the interior portions of the cutout and, in some circumstances, could evenr cause the bursting of the casing of the fuse cutout. Of course, Athe damage that wouldl be caused to the interior of the cutout and the expense necessitated in replacing such cutout under such circumstances will be appreciated. The dangers inherent to personnel in operating suchtmanual cutouts, where pressures may be generated sufiiciently strong to burst the casing ofthe cutout, will also be apparent.

From the above it can be seen that, in the present state of the oil filled, fusecutout, there is a need to provide a manually-operated fuse cutout, in which the cutout may be opened under load, without drawing a large arc between the contacts of the cutout.

It is therefore one object of this invention toprovide an oil filled, fuse cutout in which means are provided to prevent a harmful arc from being drawn upon opening of the fuse contacts under load. y

It is a further object of this invention `to providey an oil filled, fuse cutout having a pair of secondary con-` tacts in parallel with the main contacts, `such secondary contacts beingso designed as to prevent any deleterious arc from being drawn upon opening ofthe cutout under load..

In carrying out thisinvention in one form, an oil filled, fuse cutout is provided having a main pair of contacts and a secondary pair of arcing contacts, in parallel therewith. The secondary contacts include a pair of fixed contact' members, each of which is mounted in an arc-interrupting chamber. The arc interrupting chamber generates a pressure7 on opening of the secondarycontacts, sufficient to drive oil across such contactsv to interrupt the arc formed therebetween. The secondary contacts are so designed that they will not open until after the main contacts have been opened. In this manner, the oil filled, fuse cutout may be opened under load without danger of drawing a deleterious arc which may cause damage to the insulating oil and the interior portions of the cutout.

The features of this invention which are believed to be novel are set forth with particularity in the claims appended hereto. However, the invention itself, as well as the manner in which the various objects thereof are carried out, together with other objects and advantages thereof, will be better understood by reference to the following rdescription when taken in connection with the accompanying drawings in which: t

FIG. l is a perspective cut-away View of an oil filled cutout assembly made in accordance with one form of this invention; FIG. 2 is an elevation view of one form of an oil filled cutout made in accordance with this invention;

FIG. 3 is a sectional view taken on the line 3-3 of f FIG. 2;

FIG. 4 is a sectional view taken on the line 4-4 of FIG. 2;

FiG. 5 is a sectional View of the primary and secondary contacts of an oil filled fuse cutout made in accordance with one form of this invention;

FIG. 6 is a detail perspective view of the fixed secondary contact;

FIG. 7 is a perspective view in detail of a spring which may be utilized with the fusible element of this invention; and v FIG. 8 is a detailed perspective View of the movable contact assembly according to one form of thisinvention.

Referring now to the drawings in which like numerals are used to indicate like parts throughout, and in particular with reference to FIG. l, there is shown a perspective cutaway view of an oil filled, fused cutout` made in accordance with one form of this invention. The casing of the oil filled fuse cutout is generally designated as 10. The oil filled fuse cutout is inserted in a circuit by means of the cables indicated at 12 and It which provide electrical` energy to the fixed contact members 16 and 18. A manually-operable member 2t) is provided having the movable contacts 22 and 24 mounted thereon. The movable contact members 22 and 24 makeelectrical con tact with the fixed contacts I6 and 18, as shown. When desired to open the cutout it is only necessary to turn member 2t) through a 90 arc, as indicated by the arrow in FIG. 1, thus moving the contact members 22 and 24 away from members 16 and 18, thereby opening the circuit between the electrical line I2 and .14. As will be understood, when the fuse cutout is opened under load, an arc is drawn between the movable contact members 22 and 24 and the fixed contact members 16 and I8. In order` to prevent this arc from being drawn, a pair of secondary, fixed contact members 26 and 2S are provided in parallel with fixed contact members 16 and 18. Operating with the fixed contact members 26 and 28 are a pair of movable contact members 30 and 32 which are in parallel with the movable Contact members -22 and 24. The various contact members are so designedthat' the movable secondary contact members 36 and 32 Vwill maintain contact with the xed, secondary contact members 26 and 2S until the movable contacts 22 and 24 have been opened and are moved away from the fixed contact members I6 and 18. At this point, the movable contact members 30 and 32 will breakcontact with the fixed contact members 26 and 28 and, in a manner to be hereinafter described, any arc which is drawn between the members 26 and 28 and 30 and 32, respectively, will be immediately interrupted, to prevent any deleterious arc being drawn within the oil filled fuse cutout of this invention.

Referring now to FIG. 2 of the drawing, the oil filled fuse cutout is shown in sectional view, the casing in general being a metallic casing having an insulating lining 34 inserted therein. Ametallic top 36 Vis Vprovided threaded to the top of the casing 1li as indicated at 38, and a sealing gasket 40 is provided to make a tight seal therewith. Shoulders 42 and 44 are provided on the top 36 and have apertures therein to provide the means for bringing the cables 12 and 14 into the oil filled fuse cutout, as will be well understood by those skilled in this art. The electrical cables 12 and 14 are inserted into connecting means 46 and 48 wherein they make solid electrical contact with the stud devices 50 and 52. Since each side of the cutout is identical, only the right side, including tixed contact 16 and movable contact 22, will be described in detail. As shown in FIG. 2, the stud 50 goes through the secondary fixed contact and, by means of bolt 54, makes electrical connection with the primary lixed contact 16. In order -to assure a good electrical contact between the primary fixed contact 16 and the bolt 54 a flexible lead 56 is provided from the back of contact plate 16 to bolt 54. A

As shown in FIGS. 2 and 4 particularly, the contact plate 16 is mounted in the upper and lower guide plates 58 and 60 by means of pins 62 and 64. The contact plate 16 is freely positioned within the upper and lower guide plates 58 and 60'by means of slotted apertures,

best shown at 66 in FIG. 4. A helical spring 68 is provided, mounted between the end of the contact plate 16 and the insulated base, and acts to press the contact plate 16 forward irmly in contact with the movable contact means 22. By this method of mounting, the contact Aplates 16 and 18 can readily conform to any twisting of the movable contact members 22 and 24. Mountings of this type have been further disclosed in Patent 1,780,133 to Klupfel et al., issued October 28, 1930, and assigned to the sameV assignee as the present invention.

The upper or secondary fixed contact members 26 and V28 are more clearly shown in FIG. 3 of the drawing, to

which reference will now be made. As shown in FIG. 3 of the drawing, the Secondary fixed contact members 26 and 28 are each mounted within an arc-interrupting chamber 70 and 72, respectively. The secondary movable contact members 30 and 32 enter such arc-interrupting charnbers by means of the apertures74 and 75. It will, of course, be understood that the apertures 74 and 75 are large enough to allow the contact members 30 and 32 to readilyenter within the arc-interrupting chambers 70 and 72, respectively, but are made as small as is practicable with the view of allowing the ease of entering of the Contact members'30 and 32. As shown in FIG. 3 the secondary fixed contact 26 is provided with two contact faces 76 and 78, the contact face 76 making contact with the movable contact 30 while the face 78 makes an electrical connection with a contact face 80 on the bolt means 50.

The secondary fixed contact 26 is shaped in the form of a U and is pivotally mounted about a pin memberV 82, (see also FIG. 6). By means of a spring member 84,

contact member 26 is biased so as to move contact face Y From this, it can be seen,

Considering now FIG. 8 ofthe drawing, there is shown a. detailed view of the movable contact member 22 and 30. I-t will be noted that the contact members 22 and 50V are combined in the same metallic piece, the portion 22 being provided with a stud member 86 with a knurled lnut 88. YThe stud member 86 andthe knurled nut 88 are designed to clamp the U shaped fuse member 90 (FIGS.

1 and 2) lirmly to the movable plate 22. Further, the back portion of the mechanical plate forming the movable contacts 22 and 39 is provided with a channel means 92 for the reception ofthe spiraled end of spring means 94 (see FIG. 7) with a groove 96 formed in the channel member 92 to firmly hold therein the ends 98 of spring member 94. Y

Reference will now be made to FIGURES 1 and 2 of the drawing specifically, for a description of the operation of this device. It will be understood that, in the preferred form of the invention, the fuse member is in the form of a number of thin sheets of copper, Vlaminated to provide the movable contact members 22 and 24 with good electrical connection with the fuse member 90. Mounted within the manually operating means 20 is the fusible member (not shown) connecting the two ends of fuse member 96 together, such that on an over-load current the fusible portion will melt within the hollow operating member 2t). By means of the springs 94, the members 90 will be withdrawn from member 20 to thereby rapidly extinguish any arc which is drawn during the blowing of the fusible element.

When it is desired to open the oil lled cutout of this invention, while a load is still being carried by the cutrout, that is, while the lines 12 and 14 are still energized,

the manual operating member 26 is rotated in the direction of the arrow shown in FIG. 1. On rotation of member 20 the movable contact plates 22 and 24 will move out of contact with the fixed contact plates 16 and 18 in the manner shown more specifically in FIG. 4 of the drawing.v As the movable member 2i) is being rotated in the direction of the arrow, the secondary movable contact members 30 and 32 will begin to be withdrawn from the arc-interrupting chambers 70 and 72, but will be maintained in contact with the secondary fixed contact members 26 and 28, as shown more specifically in FIG. 5 of the drawing. After the movable contact plates 22 and 24 have moved completely free of the xed contact plates 16 and 18, the secondary movable contact members 30 and 32 will have moved beyond the first beveled side of the contact face 76 of the contact plates 26 and 28 and will have allowed spring means 84 to have opened the contacts 78 and 8i). Immediately after contacts 78 and 80 have opened, the contact 30 will move free of the contact plate 76. By this operation, the opening of the contacts 78 and 80 draws an arc between such contacts thereby generating a pressure in the oil which is in the arc-interrupting chambers 78 and 72. The oil pressure generated will be forced around the U- shaped contact-member 26, which forms a partial partition in chambers'70 and 72, and out across the contact face 76 through the aperture 74. As the oil pressure is blasted out over the face 76 and through aperture 74, it will blow out any arc which has been drawn between the contact member 36 and the contact face 76, on contact member`26. Of course, in a similar manner, the arcV which is drawn between the movable contact 32 and the fixed contact 28 will also be blown out through the aperture 7 5 by the oil pressure which is generated within the arc-interrupting chamber 72.

Thus, by causing the first arc to form within the interior portion of the arc-interrupting chambers '70 and 72, oil pressure is generated which will blow out around the secondary fixed contacts 26 and 28. This pressure will blast oil across the secondary contacts, when opened, effectively interrupting the arc formed therebetween. that the rapid interruption of the arc drawn in opening the oil lled, fuse cutout of this invention is obtained without danger of contamination of the oil and without danger of building up an extreme pressure in the oil lilled, fuse'cutout which would cause damage to the interior of the cutout, or, under certain circumstances, could cause an explosion of the casingof thecutout. Thus, by means of the oil iilled, fuse cutout of this invention, the cutout can be manually chamber contact face and said onecontact face opened while the lines are energized without danger of drawing a larger power arc in the cutout with the resultant danger to personnel or damage to the cutout and .the parts thereof; t A

Of course, it will `be obvious that this invention may also be used in oil filled cutouts, which are not provided secured by Letters Patent of the United States is:

1. An oil filled, cutout with arc interrupting means comprising a pair of main contacts, a pair of secondary contacts in parallel circuit relation with said main contacts, said secondary contacts comprising ya'par of fixed Contact members and a pair of movable contact members, a pair of arc interrupting chambers, each of said pair of fixed contact members being pivotally mounted in one of said pair of arc interrupting chambers and forming a partial partition therein, said movable contact members being movably mounted exteriorly of said arc interrupting with a portion of each of said movable contact members movable into one of said arc interrupting chambers to contact said fixed contact therein, each said pivotally fixed contact memberhaving a pair of contact faces, one contact face engageable with a stationary contact face in each of said arc' interrupting chambers, the other of said contact faces engageable with said portion of said movable contact, a small aperture in eachtof said arc interrupting chambers for entry of said portion of each of said pair of movable contact members, oil in each said arc interrupting ,chamber responsive to an arc drawnV therein to generate pressure in each of said arc interrupting chambers, means for opening tacts` and said` secondary contacts, said main contacts opening before said secondary contacts, saidother contact face of said fixed contact member cooperating with said main consaid movable contact member to disengage said stationary .i

just prior to the opening of said` secondary contacts, said secondary contacts opening in said arc interrupting chamber and draw ingan arc therebetween, said oil in said arc interrupting chamber responsive to an arc drawn between` said stationary contact face and said contact face to force oil around said partial partition and out said aperture to interrupt said arc drawn between said secondary contacts.

2. An oil iilied, fuse cutout with arc interrupting means comprising a pair ofimain contacts,a pair of ,secondary contacts in parallel with said main contacts, means for opening said main contacts and saidsecondary contacts, said pair of main contacts opening before said pair of secondary contacts, said'secondary' contacts comprising a xed contact member, and aV movable contact member, said fixed contact member mounted in an arcinterrupting chamber, means in said arc-interrupting chamber responsive to an arc for interrupting such arc, said fixed contact member being pivotally mounted in said arc-interrupting chamber, means in said arc-interrupting chamber forming a stationary contact face, means on said fixed contact member forming a contact face engage able with said stationary contact face, means biasing said fixed contact member to hold said contact face out of engagement with said stationary contact face, said movable contact member overcoming said biasing means and causing engagement of said contactr face and said stationary contact face when said secondary contacts are closed, means on said fixed contact member cooperating with said movable contact member lto cause said contact face and said stationary contact face to move out of engagement during the opening movement of said secondary contacts, but prior to drawn between said contact face and said stationary contact face activates said arc interrupting means to thereby interrupt an arc drawn between said movable contact member and said iixed contact member.

3. An oil filled, fuse cutout as claimed in claim 2 in which said means on said xed contact member cooperating with said movable contact member comprises a beveled contact face having two beveled surfaces, one of said beveled surfaces being in engagement with said movable contact member when said contact face and said stationary contact face are engaged and the other of said beveled surfaces engaging said movable contact member when said Contact face moves out of engagement with said stationary contact face not open.

4. An oil filled, fuse cutout as claimed in claim 2 in which said arc interrupting means is oil and said arcinterrupting chamber Ais provided with a small aperture to allow entry of said movable contact member, such that an arc drawn between said contact face and said stationary contact face generates oil pressure to force oilv out of said aperture between said xed contact member i and said movable contact member.

5. An oil filled, fuse cutout as claimed in claim 4 in which said iixed contact member forms a partial partition in said arc-interrupting chamber and lsaid oil is forced around said partition by an arc drawn between said contact face and said stationary contact face.

References Cited in the iile of this patent UNITED STATES PATENTS' Paul a Feb, 13,

opening thereof whereby an arcand said secondary contacts areV 

2. AN OIL FILLED, FUSE CUTOUT WITH ARC INTERRUPTING MEANS COMPRISING A PAIR OF MAIN CONTACTS, A PAIR OF SECONDARY CONTACTS IN PARALLE WITH SAID MAIN CONTACTS, MEANS FOR OPENING SAID MAIN CONTACTS AND SAID SECONDARY CONTACTS, SAID PAIR OF MAIN CONTACTS OPENING BEFORE SAID PAIR OF SECONDARY CONTACTS, SAID SECONDARY CONTACTS COMPRISING A FIXED CONTACT MEMBER, AND A MVABLE CONTACT MEMBER, SAID FIXED CONTACT MEMBER MOUNTED IN AN ARCINTERRUPTING CHAMBER, MEANS IN SAID ARC-INTERRUPTING CHAMBER REPONSIVE TO AN ARC FOR INTERRUPTING SUCH ARC, SAID FIXED CONTACT MEMBER BEING PIVOTALLY MOUNTED IN SAID ARC-INTERRUPTING CHAMBER, MEANS IN SAID ARC-INTERRUPTSAID FIXED CONTACT MEMBER FORMING A CONTACT FACE ENGAGEABLE WITH SAID STATIONARY CONTACT FACE, MEANS BIASING SAID FIXED CONTACT MEMBER TO HOLD SAID CONTACT FACE OUT OF ENGAGEMENT WITH SAID STATIONARY CONTACT FACE, SAID MOVABLE CONTACT MEMBER OVERCOMING SAID BIASING MEANS AND CAUSING ENGAGEMENT OF SAID CONTACT FACE AND SAID STATIONARY CONTACT FACE WHEN SAID SECONDARY CONTACTS ARE CLOSED, MEANS ON SAID FIXED CONTACT MEMBER COOPERATING WITH SAID MOVABLE CONTACT MEMBER TO CAUSE SAID CONTACT FACE AND SAID STATIONARY FACE TO MOVE OUT OF ENGAGEMENT DURING THE OPENING MOVEMENT OF SAID SECONDARY CONTACTS, BUT PRIOR TO OPENING THEREOF WHEREBY AN ARC DRAWN BETWEEN SAID CONTACT FACE AND SAID STATIONARY CONTACT FACE ACTIVATES SAID ARC INTERRUPTING MEANS TO THEREBY INTERRUPT AN ARC DRAWN BETWEEN SAID MOVABLE CONTACT MEMBER AND SAID FIXED CONTACT MEMBER. 